In preparation for filing of this application, a pre-examination patent ability search was performed. Among the classes and subclasses reviewed were Class 123, subclasses 27R, 65B, 65BA, 68, 198C, 213, 257, 268, 316, 528, 533, 559.1, 561, 565, and 564. Computer searching was also done on the PTO patent database.
The search uncovered the following:
Designs for two stroke internal combustion engines are disclosed in the art that use positive displacement pumps to charge the cylinder with air prior to ignition. Compressed air is also used to scavenge the cylinder of combustion products during the exhaust cycle of the engine. Various methods of charging the cylinder with the compressed air produced by a positive displacement pump are disclosed in the art. Often a camshaft actuated poppet valve closing off the cylinder from the air passage leading from the air compressor is timed by the camshaft to open and allow the compressed air to enter the cylinder during part of the exhaust cycle to fill the cylinder and push out remaining exhaust gases before the exhaust port has closed.
One such design is disclosed in the U.S. Pat. No. 4,671,218 issued to Weiland. In this patent there is disclosed a gear type positive displacement pump used to charge a holding chamber located above the cylinder with compressed air through which a valve stem projects to the valve face that seals the intake port located in the floor of the holding chamber from the cylinder beneath it. A crankshaft driven camshaft actuates the intake valve while the exhaust ports are open, which are located in the cylinder wall just above the face of the piston when it is at bottom dead center, allowing compressed air from the compressor to fill the cylinder and scavenge the cylinder of remaining exhaust gases. While this design appears to be simple and straightforward it has the disadvantage of using a camshaft to operate the intake valve and such a design adds to the cost and complexity of the machine and diminishes its performance by using engine output to operate the camshaft and valve. It also has the disadvantage of fresh air being able to enter the open exhaust ports before they close since the camshaft is timed to open the intake valve and allow compressed air from the compressor into the cylinder while the exhaust ports are still open. This will reduce the temperature of the exhaust gases reducing the effectiveness of catalytic converters designed to reduce exhaust emissions, which require high exhaust temperatures for maximum effectiveness. The solution to this problem is a combustion-operated valve between the compressor and the cylinder, sealing the cylinder from the compressor outlet that eliminates the need for a camshaft and closes before fresh air from the compressor can reach the exhaust port. No means are shown to transfer the energy of combustion directly to the compressor gears during the power stroke of the engine. Such a valve exposes the compressor gears to the forces of combustion thereby producing a transfer of power to them during the power stroke of the engine
The blower types described and illustrated in the patents found during a patent search are usually of the Roots type as disclosed in the Toepel Pat. No. 4,539,948, the Green Pat. No.5,746,163 and several others, turbocharger designs as disclosed in the Toepel Patent and Sweeney Pat. No. 5,878,703 and others, or of the radial type as disclosed in the Rocklein Pat. No. 4,860,699, the Covone Pat. No. 2,851,021, and others. Only in the Weiland Patent and Figliuzzi Pat. No. 5,179,921 do we see a positive displacement gear pump used as a means to force air into the engine. In neither of these designs or in any of the other patents listed is shown an engine in which the compressor is located in the engine and directly compresses air between the compressor and the reciprocating means without the use of intervening valve means to separate the compressor from the combustion process. Nowhere is such a valve means shown that does not use crankshaft power to operate it.
It is therefore an important object of one embodiment the present invention to eliminate intake valves from a compressor charged two cycle engine by placing a positive displacement gear type air compressor in the engine head which compresses combustible material directly between the compressor and the reciprocating means thereby receiving a transfer of power to the compressor gears during the power stroke of the engine.
It is an important object of another embodiment of the present invention to eliminate the need for a camshaft to operate a valve between the compressor and the cylinder with such a valve controlled to prevent a flow of fresh air into the exhaust port during the exhaust process of the engine.
A third object of another embodiment of the present invention is to further simplify the engine design by combining the functions of the piston and rod into one reciprocating part to make the engine more durable.
The invention comprises a two-stroke internal combustion engine. The simplest embodiment having a housing made of two identical parts bolted together for easy manufacture, strength or assembly and disassembly. The housing has an intake port located in the uppermost wall of the housing for passing air into a gear type air compressor. The engine includes the air compressor formed by two partial cylinders enclosing the two gear shafts of the air compressor within the upper part of the housing below the intake port. The gear shafts output shafts pass through holes in the outer housing walls for the takeoff of power, and one of them is connected by rotational means connected to the output shaft of the crankshaft for a transfer of power between them. A passage for holding compressed air connects the outlet side of the air compressor to the top end of the cylinder confining the piston of the engine so the compressor gears and the piston are simultaneously exposed to the forces of combustion during the power cycle of the engine. A fuel injector nozzle is located in the intake port for injection of fuel into the passage. The piston is rotatably connected to the rod which is rotatably connected to a crankshaft located in the lower part of the housing space for converting the forces of combustion into useful torque. The crankshaft output shafts pass through identical holes in the walls of the housing. The crankshaft, gear shafts and reciprocating part have internal passages (not shown) for the passage of lubricant to areas of the engine requiring lubrication. Lubricant is pumped into these passages by a conventional oil pump, which is located in the bottom of the housing, to lubricate the engine. An exhaust port is located in the cylinder wall above the bottom dead center position of the piston face and allows exhaust gases to escape the cylinder after the power stroke. Fuel timing and pressure regulation means are provided to allow correct amounts of fuel to be injected into the engine at the proper intervals. This machine has an improved performance compared to other types of two cycle engines because the piston and the compressor gears are exposed simultaneously to the forces of combustion. The power generated by them is combined through power transfer means connecting an output shaft of the crankshaft to an output shaft of a gear shaft.
In any embodiment of this invention conventional sensors and engine management systems can be included to produce optimum engine performance. A conventional oil pump and oiling system can be included to provide oil to the cylinder walls, crankshaft bearings, rod bearings and gear shaft output rod bearings, conventional bearings means included for support of rotating parts. Conventional fuel supply means for supply of fuel to the fuel injector, conventional spark ignition means can be included to ignite the fuel and air mixture. A water jacket can be included to provide cooling means to embodiments that do not include a water jacket and if necessary an engine driven water pump included to circulate water through the water jacket and a radiator if needed, a fan to circulate air through the radiator.
This discussion has outlined some of the more important objects of the invention. These objects should be construed as illustrative of the more salient features and applications of the present invention. Many other important results can be obtained by applying the disclosed invention in different ways and modifying it within the scope of the disclosure. Accordingly, by referring to the detailed descriptions of the various embodiments taken together with the accompanying drawings and claims a more complete understanding of the invention may be ascertained.